It is well known in the art to produce aluminum-zirconium glycine solutions. However, these solutions are typically limited to concentrations of 40% solids or less. Solutions which contain more than 40% solids produced by method known in the art typically gel or become extremely viscous within a short period of time after their formation. Because of this commercially available solutions are typically limited to 35 weight percent solids or less.
Methods which are known in the art for producing aluminum-zirconium glycine solutions include, U.S. Pat. No. 2,814,584 to Daley which teaches Buffered Antiperspirant Compositions containing 5 to 50 weight percent of the antiperspirant constituents. However, the preferred range is 10 to 30 weight percent. The solutions are formed by blending a hafnium or zirconium salt, a basic aluminum salt, water and urea.
U.S. Pat. No. 2,854,382 to Grad teaches Zirconyl Hydroxy Chloride Antiperspirant Compositions containing 5 to 30% (total) of zirconyl hydroxy chloride and aluminum chlorhydroxide. However, even at 30% solids, gelling is a problem and high amounts of glycine must be added to prevent the gelling. To prevent gelling of a 30% solids solution, approximately 17.5% by weight of glycine is required. The compositions are formed by blending the desired amounts of zirconyl hydroxy chloride, aluminum chlorhydroxide, glycine and water.
U.S. Pat. No. 2,906,688 to Beekman teaches solutions of zirconyl and aluminum halohydroxy complexes. These solutions can contain up to 40% of the complex as shown in their Example I. The complexes are formed by mixing a zirconium oxyhalide and aluminum hydroxy halide and heating the mixture with agitation until a liquid results. This patent does not teach the use of glycine to buffer or add stability to the solutions.
U.S. Pat. No. 4,148,812 to Rubino et al. teaches a method for making basic zirconium-amino acid gels by reacting a water soluble salt of an amino acid and water soluble zirconium salt to form a precipitate and recovering the precipitate which is a gel. The basic zirconium-amino acid gels are then used to form complexes with conventional aluminum and/or zirconium antiperspirant systems. Rubino does not teach that the complexes are stable at higher solids concentrations in the final complex.
U.S. Pat. No. 4,028,390 to Rubino teaches astringent complexes produced from an aluminum compound and a basic zirconium carbonate gel. These complexes can also contain glycine. The method taught in U.S. Pat. No. 4,028,390 for forming the astringent complexes is to add the glycine to the aluminum compound and then add the zirconium carbonate and heat to form the complex. This patent does not teach a method for combining zirconium carbonate and glycine and heating them to directly form coordinate bonds between the zirconium and glycine prior to complexing with the aluminum compound. Further this patent only teaches solution which contain 5 to 20 weight percent (solids basis) of the complex.
U.S. Pat. No. 4,331,609 to Orr teaches aqueous solution-stable antiperspirant complexes comprising an aluminum compound, a zirconium compound, a water soluble neutral amino acid and an inorganic acidic compound. The solutions comprise 32 to 38% by weight of solids, exclusive of the neutral amino acid present. The solutions are formed by mixing the components together.
It is an object of this invention to show a method for producing stable, concentrated aluminum-zirconium glycine solutions.
It is further an object of this invention to show stable, aqueous aluminum-zirconium glycine solutions with contain 45 to 50 weight percent solids.